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Square root

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by saitjordan » Sat Jan 31, 2009 10:52 am
This is probably fairly elementary, but how do you quickly take the square root of a number that is not a perfect square like say 18. In one question they found the square of 18 to be 3*sqrt(2). How do I do that quickly?
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by DanaJ » Sat Jan 31, 2009 10:56 am
My advice is to use prime factorization. 18 = 2*3*3 = 2*(3^2), so sqrt(18) = 3sqrt(2).
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by dmateer25 » Sat Jan 31, 2009 10:58 am
Break 18 down into primes.

18 = 2 * 3 * 3

sqrt of 2 * 3 * 3

you can see there are 2 threes inside the square root. So you pull one out. This will leave you with 3sqrt2
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Thanks

by saitjordan » Sat Jan 31, 2009 11:15 am
Thanks guys that helps a lot.
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